You're a little off on your recommended usage for this. For a paladin, using Flash of Light would work better, it is a faster cast and allows it to stack quicker. Also interesting to note, you can use this at the same time as Scrolls of Blinding Light, which means the effect can stack up really quick.
A holy paladin with Scrolls of Blinding Light can have this procced 5 times in about 6 seconds...if that paladin keeps spamming flash of light the buff will stay active and you can essentially have it maxed for 24sec.
A holy paladin with Scrolls of Blinding Light can have this procced 5 times in about 6 seconds...if that paladin keeps spamming flash of light the buff will stay active and you can essentially have it maxed for 24sec.